CJ6, I found this source on the web. Looks interesting. There are also very good books on Mausers.
As with any internet source, take it with a grain of salt. That site seemed to be good IMO.
Not sure if you know Mausers, but they are a very good design especially for their day. Generally, if you stick with the original chambering, they are fine. 7x57 is a very good cartridge, again my opinion.
Of note with Mausers, they were made under contract for many countries and in many factories. They were also made in Germany, Austria, etc, for Germany of course. From my brief review of yours, early rifles were manufactured by Ludwig & Lowe, which is good. Later rifles like yours seem to have been produced in Oviedo. What I would research if I were in your position, is the reputation of the manufacturing in Oviedo Spain. From that you can make some decisions/assumptions.
It almost seems as though the Mauser design was ahead of the metallurgy at the time. Easy to make that judgement at this point in history. Having said that, they were very adequate as designed and manufactured.
The condition of the rifle has a lot to do with it as well. Many saw service, and the priming might have been corrosive. It is common to find them with rough bores. Amazingly, some of those shoot quite well.
One last thing, the 1893 Spanish is a "small ring" the 1898 design is a "large ring" Mauser. Both are very good, the latter is physically larger, and has additional safety measures engineered into them. Third lug, etc.
Best of luck, Peter.